#include <iostream>
#include <cstdio>

using namespace std;
int main()


{
int n1,n2,n3,suma=0;  
    
    
    cin>>n1; cin.ignore();
    cin>>n2; cin.ignore();
    
    do
    {
    cin>>n3; cin.ignore();

    suma=n1+n2;
    
    
   
    n1=n2;
    n2=n3;
    }
    while(n3!=suma);
    
    
    
    
    cout<<endl<<"Jest!";

      
getchar();
return 0;
}